Functional neuroimaging grew from the scientific desire to “see” the living human brain at work, tracing its blood flow and metabolic processes rather than only its anatomy. Early work such as Angelo Mosso’s 19th-century human circulation balance presaged this field by noting blood redistribution during mental activity. The first true functional modalities emerged in the 1970s with Positron Emission Tomography (PET), pioneered by researchers including Michael Ter-Pogossian, Michael Phelps, and Edward Hoffman, who developed PET to detect gamma rays from radiotracers tracking cerebral glucose metabolism and blood flow. In the early 1990s, Seiji Ogawa elucidated the blood-oxygen-level-dependent (BOLD) contrast that underlies modern functional Magnetic Resonance Imaging (fMRI), allowing non-invasive maps of brain activity based on changing magnetic properties of oxygenated versus deoxygenated blood. Techniques matured through work by figures such as John Belliveau and Kenneth Kwong (fMRI signal demonstrations, 1991), and the field went on to standardise methods for task-based and resting-state imaging (e.g., Bharat Biswal’s resting-state fMRI discoveries in the 1990s). In simple terms, PET uses injected radio-labelled molecules to measure metabolic activity, while fMRI detects localized increases in blood flow as proxies for neurons firing, with computers reconstructing three-dimensional activity maps from signal changes.

From a Christian perspective, these innovations can be seen as part of the God-given mandate to “fill the earth and subdue it” (Genesis 1:28), wisely exploring human design to heal and understand (1 Timothy 4:8). They reveal the dignity of the embodied mind, affirming that the brain’s functional unity reflects the imago Dei even as they humble us before the interconnected complexity of God’s creation.

Clinically and societally, fMRI and PET have revolutionised diagnosis and treatment of neurological disorders, informed mental health interventions, enabled presurgical brain mapping, and deepened personal insight into cognition and behaviour, enhancing wellbeing in communities by fostering evidence-based care and compassionate understanding of conditions that affect human flourishing.